Abstract

Studies of hospital performance highlight the problem of 'failure to rescue' in acutely
ill patients. This is a deficiency strongly associated with serious adverse events,
cardiac arrest, or death. Rapid response systems (RRSs) and their efferent arm, the
medical emergency team (MET), provide early specialist critical care to patients affected
by the 'MET syndrome': unequivocal physiological instability or significant hospital
staff concern for patients in a non-critical care environment. This intervention aims
to prevent serious adverse events, cardiac arrests, and unexpected deaths. Though
clinically logical and relatively simple, its adoption poses major challenges. Furthermore,
research about the effectiveness of RRS is difficult to conduct. Sceptics argue that
inadequate evidence exists to support its widespread application. Indeed, supportive
evidence is based on before-and-after studies, observational investigations, and inductive
reasoning. However, implementing a complex intervention like RRS poses enormous logistic,
political, cultural, and financial challenges. In addition, double-blinded randomised
controlled trials of RRS are simply not possible. Instead, as in the case of cardiac
arrest and trauma teams, change in practice may be slow and progressive, even in the
absence of level I evidence. It appears likely that the accumulation of evidence from
different settings and situations, though methodologically imperfect, will increase
the rationale and logic of RRS. A conclusive randomised controlled trial is unlikely
to occur.

All truth passes through three stages.

First, it is ridiculed.

Second, it is violently opposed.

Third, it is accepted as being self-evident.

Arthur Schopenhauer (1788–1860), German philosopher

Introduction

Hospitals now treat increasingly complex patients. Despite the growth of technology
and the development of new medications, 10% to 20% of hospitalised patients develop
adverse events, with an overall hospital mortality of 5% to 8% [1-3]. Importantly, an estimated 37% of these events may be preventable [3]. Multiple studies from Europe, the US, and Australia have also confirmed deficiencies
in the way hospitals and 'traditional' models of care respond to acute illness in
the wards [4-7]. One deficiency of the hospital system's approach to acute illness is the problem
of 'failure to rescue' [8]: failure to deliver rapid and competent care to an acutely ill ward patient. Traditionally,
hospitals have left such rapid responses to either the parent unit or cardiac arrest
teams. Unfortunately, the parent unit doctors are often unable to attend the patient
rapidly or are not specifically or sufficiently trained in acute resuscitation [4-7]. Although cardiac arrest teams have been around for decades, they often arrive at
the end of the disease cascade, are unsuccessful in greater than 85% of patients,
and patients so treated may survive the arrest but carry a high risk of hypoxic brain
injury [9-11]. These observations suggest that earlier recognition of disease progression provides
the opportunity to avert major adverse events in many cases. In others, it provides
the opportunity to put in place a terminal care plan that prevents unnecessary interventions
and an undignified death.

Early recognition of an 'at-risk' situation is important in ensuring patient safety.
Physiological warning signs (instability) of impending cardiac arrest have been repeatedly
demonstrated to be common [6,8-10] and to precede such events by several hours, with 60% to 84% of cardiopulmonary arrest
patients showing physiological instability within 6 to 8 hours of the event [12,13]. However, in traditional systems, the hospital's response is often late and inadequate
[12-24]. The outcome of this approach has not improved in 50 years. Clear evidence of inadequate
ward care was provided by a study from the UK [6] which found that, prior to intensive care unit (ICU) admission, suboptimal management
of oxygen therapy, airway, breathing, circulation, and monitoring occurred in over
half of patients. These errors were essentially due to the failure to apply or appreciate
the need for basic resuscitation measures. Major causes of suboptimal care included
failure of organisation, failure to appreciate clinical urgency, and failure to seek
advice [6]. In summary, there is much evidence that 'failure to rescue' is common in patients
at risk for major adverse events. There is also evidence that failure to appreciate
the clinical urgency of situations is common, that the knowledge and skills to deal
with such situations are limited among ward doctors and nurses, and that, in most
patients, there are warning signs for a long enough period to allow appropriate action
to be taken.

Critical care for the critically ill anywhere in the hospital

The concept of rapid and early rescue is well established in various fields of medicine,
especially in trauma, cardiology, and, more recently, severe sepsis and septic shock
[25-27]. It would make sense to apply these concepts to critical illness in general, wherever
it may occur in the wards, and to use an RRS to deliver early intervention by specifically
trained teams. In this regard, it is important to realise that, in most hospitals,
the expertise exists to rapidly deliver the skills and knowledge to the bedside when
necessary to deal with critical illness. Critical care physicians and critical care
nurses can theoretically deliver such expertise anywhere in the hospital within minutes.

The field of critical care medicine has made considerable progress in improving outcomes
of critically ill patients. Given that most acute illness develops through stages
of deterioration, the logical step surely would be to bring intensive care equipment
and expertise to any acutely ill patient, irrespective of location within the hospital,
in what has been described as creating a 'critical care system without walls' [28]. The medical emergency team (MET) brings this expertise to the patient in a timely
manner and supplies the 'efferent arm' of this process of identification of at-risk
patients and rapid delivery of appropriate care, designated recently as the rapid
response system (RRS) [29].

Because the care of critically ill patients is their core specialty competency, intensive
care doctors and nurses are ideally placed to provide immediate care to patients who
are critically ill: they are acute illness specialists. The value of specialists in
expert management of specific disease conditions is widely accepted. Specialists are
so named because they are trained with particular skills and in-depth knowledge. It
would seem illogical for inadequately trained doctors to treat acutely ill patients
instead of critical care physicians and nurses being responsible for their management
[30].

Common sense or science

The concepts presented above seem, at face value, to simply represent common sense.
However, in an era of 'evidence-based medicine', the efficacy of the MET and utility
of the RRS have been criticised for lacking sufficient high-quality evidence in the
form of randomised controlled trials. Meta-analytical techniques have been used to
demonstrate the weakness of such evidence [31,32]. For example, in a recent meta-analysis by Winters and colleagues [32], although the respective relative risks (95% confidence intervals) for hospital mortality
and cardiac arrest were 0.76 (0.39 to 1.48) and 0.94 (0.79 to 1.13) (suggesting a
benefit), the authors concluded that the heterogeneity of the studies and wide confidence
interval suggest that adopting RRS as a standard of care is premature and possibly
wrong.

In our opinion, however, there are unique issues surrounding RRS which need to be
taken into account when interpreting the available evidence. First, these systems
are not simple tablets whose efficacy or effectiveness can be tested in double-blind
randomised controlled trials [33]. Second, these systems are complex human activities. They require consideration of
several important anthropological, organisational, political, logistic, and administrative
aspects [29]. These aspects profoundly affect the implementation, performance, and efficacy of
such systems. Third, acceptance of the cultural changes associated with the introduction
of RRS requires time, making early assessment of such systems flawed and non-representative
of their later performance [29,34]. Accordingly, the challenges surrounding the implementation of such systems require
detailed discussion.

The challenges of implementing rapid response systems

Even when the concept of RRS is believed to be advantageous, the actual implementation
entails overcoming a myriad of barriers: political, financial, educational, cultural,
logistic, anthropological, and emotional (Table 1). Some of these challenges are particularly important to consider.

Rapid response system breaks with 'tradition'

The culture of ward doctors managing acutely unwell patients is changed by the introduction
of RRS. We have seen this at our institution, where ICU doctors and nurses are no
longer viewed as experts confined to the 'ivory tower' of the ICU but are now constantly
assessing and helping to treat 'at-risk' patients in general wards [35]. This paradigm shift in our hospital culture and medical practice has changed how
the roles of ICU and hospital doctors and nursing staff are being viewed. Nevertheless,
allegiance to the traditional approach of initially calling the parent medical unit
doctors when there are objective early signs of clinical deterioration is difficult
to eradicate: 72% of nurses surveyed continue to choose to call the parent unit first,
despite several years of RRS operation [36]. It is an extraordinary challenge to change 'culture'.

Rapid response systems challenge medical 'power'

The MET patient is created by the environment and the disease and not by the disease
per se. This implies a mismatch between resources and needs as a component of the syndrome.
The arrival of the MET brings a critical care environment to the bedside. In a sense,
when an MET syndrome develops, it could be argued that both the hospital and the patient
are 'sick' [37]. Occasionally, errors that underlie the development of the MET syndrome naturally
surface during an MET review [38]. This often causes parent medical unit doctors and ward nurses to worry about criticism.
It is important to emphasise that the MET service is 'hospital policy' and that no
hospital staff should be reprimanded for calling the MET. Similarly, it is vital to
reiterate that the MET intervention does not represent an attempt by the ICU staff
to take over patient management [35]. Despite these assurances, many doctors remain uncomfortable over the perceived loss
of control and the fact that nurses can activate the MET without requiring permission
from them. Ignoring these problems and not seeking to reassure medical staff is likely
to increase the chance of failure of an RRS.

Rapid response systems give ward nurses more power

As nurses are in direct patient contact most of the time, they also need and call
an MET most. Surveys have shown that a majority of nurses welcome the availability
of an MET service, with 84% feeling that it improves their work environment and 65%
considering it a factor when seeking a new job in an institution [39,40]. The MET enables the nurse to exercise independent judgement and to call for immediate
assistance should the patient fulfill a predetermined set of clinical criteria. He
or she can bypass the delay often apparent with calling for help through a hierarchy
of medical and nursing staff. This is seen even in experienced nurses, who in an Australian
survey were found to be more likely to activate an MET [40]. Nurses are the most powerful and numerous allies of RRS.

Staff may be ashamed to call a medical emergency team

The issue of professional pride or fear of blame has to be overcome. Activation of
an MET does not imply that ward personnel are incapable or unwilling to manage the
patient themselves. This aspect must be emphasised in educational and preparation
sessions. Hospital administration supporting the MET system needs to engage all staff
in a re-orientation from individual to system thinking [41]. Policies should be widely available and regularly reinforced and communicated by
senior hospital staff. As data collection and audits are part of the feedback arm
of the MET [29], positive action should be taken to encourage favourable staff behaviour.

Ward monitoring needs constant improvement

Several studies have shown a circadian pattern of activation of MET [42-44]. This peculiar variation is most likely explained by the interaction between ward
staff caring for the patient and the monitoring tools used. Such variation is absent
in the ICU, where more extensive monitoring and a higher nurse/patient ratio are standard
[43]. Recordings of early signs of critical conditions were 7.7 times more frequent than
late signs, with nurses accounting for 86.1% of these [45]. Interestingly, in that study, 17.8% of all recordings of early signs and 9% of late
signs were judged by nurses to be 'usual for the patient'. These commonly included
mild hypoxaemia, hypercarbia, and hypotension. As the MET call criteria depend heavily
on physiological alteration of signs, poor monitoring equipment, methods, and recognition
by staff may be a major stumbling block in improving outcomes and RRS performance.
Regular staff educational programs and audits of technology and processes of care
are necessary to minimise these problems.

Major delays in calling a medical emergency team

Despite positive attitudes toward the MET system, nurses may not always follow the
predetermined MET activation criteria or may fail to recognise when assistance is
required. Daffurn and coworkers [46] showed, in a study conducted 2 years after implementation of an MET system, that
nurses variably correctly identified scenarios warranting an MET call in 17% to 73%
cases. Hypotension did not appear to alert nurses to summon assistance, and some nurses
would still call a resident rather than the MET in the presence of severe deterioration
and patient distress. Unpublished data from our experience confirm that delays in
calling an MET are associated with increased in-hospital mortality (Figure 1) and that even a minor delay has a substantial effect on outcome. These observations
highlight another challenge in the adoption and research of such systems. If deficient
MET systems are tested, they may fail to show a clinical benefit. No matter how good
the system is, major methodological challenges need to be overcome to evaluate such
systems in a rigorous and clinically relevant way.

Figure 1. The effect of delay in medical emergency team (MET) calls on mortality in two cohorts
of patients at the start of an MET program and 5 years later. *p < 0.001; **p < 0.004.

Evaluating the medical emergency team system

Medical technologies and drugs are assessed using methodology favouring the statistical
power of large numbers and certain study designs. This approach dismisses real-life
relevance, Bayesian logic, and common sense as too biased and methodologically flawed.
Though scientifically valid, this approach fails to achieve a balance between rigour
and real-life evidence in assessing process improvement [33]. The effectiveness of the MET is related to a systematic change in the way hospitals
deliver care. An alternative, 'pragmatic science' approach by Berwick [47] promotes tracking effects over time, integrating detailed process knowledge into
the work of interpretation, using small samples and short experimental cycles of change,
and using multifactorial designs in evaluating system change. According to this paradigm,
common sense practices like bringing critical care expertise to acutely ill ward patients
might not require randomised controlled trials and other evidence-based methodology
before incorporation into practice. We note that no randomised multicentre double-blind
controlled trials exist to test the effectiveness of hand-washing by doctors and nurses.

Even if one intended to conduct a randomised controlled trial of METs within an institution,
this would be made nearly impossible by the Hawthorne effect [48]. This effect would artificially lead to an improvement in the care of control patients,
with doctors and nurses imitating the intervention being studied. It is also unethical
to randomly assign acutely ill patients, as it would deny potentially life-saving
interventions to those randomly assigned to 'placebo'. Adequately matched case-control
studies, though not considered sufficiently rigorous, may avoid some of the shortcomings
[49]. As a consequence, only hospitals can become the unit of randomisation (cluster randomisation)
[50]. In the largest cluster randomised study of METs [51], the Medical Emergency Response Improvement Team (MERIT) study, investigators randomly
assigned participating hospitals to standard care or the introduction of an MET. The
result was an increased overall MET calling rate in MET hospitals but no substantial
effect on cardiac arrest, unplanned ICU admissions, or unexpected death. However,
that study had major shortcomings from severe lack of statistical power due to the
large variance in outcome incidence and wide standard deviation and the lower-than-expected
incidence of the outcome measures under investigation. Given the incidence and variance
of such outcomes, more than 100 hospitals would have been needed to show a 30% difference
in the composite outcome, whereas only 23 hospitals were actually recruited. Inadequate
and non-uniform implementation of the MET was also an issue in MERIT as there was
a lack of a continued educational process throughout the study period. Furthermore,
the call rate in MERIT was much lower (<20%) than that seen in hospitals implementing
successful MET programs. This is not surprising as the evaluation time was only 6
months. Typically, such systems require more than a year or two to mature.

Before-and-after studies

The current literature on MET shows many examples of before-and-after studies dealing
with single-centre data [52-56]. Inherent within this type of evidence is the lack of rigour and generalisability.
Furthermore, the magnitude of the effect of the MET may be influenced by institution-specific
administrative features and policies. Buist and coworkers [52] showed a 50% reduction in the incidence of cardiac arrests, whereas a study by DeVita
and colleagues [54] reported a 17% decrease. Data from our institution [53] revealed a 65% relative risk reduction in a 4-month comparison study in surgical
patients. Of note, almost all studies point to an effect of the MET in reducing cardiac
arrests. The type of patients evaluated does appear to differ in outcomes, with surgical
postoperative cases benefiting the most in terms of mortality reduction [55,56]. Despite methodological shortcomings, the MET has proliferated in hospitals, although
controversy continues over whether it should be a standard of care (Table 2). Even if one believed in the concept of MET, adopting the MET poses major political
and logistic challenges. One has to convince colleagues, educate nurses and doctors,
maintain awareness, and ensure collegiality and performance [34,57-59]. Time is needed for the MET concept to 'bed in' [58] in order to reap its benefits in a substantial manner. Repeated education and periodic
assessment of site-specific obstacles to utilisation of MET should be addressed [59]. If education and staff awareness can be maintained after the initial introduction,
the MET system continues to increase in efficacy. Short-term studies may therefore
underestimate its impact [34]. RRSs with their MET components are not easy, nor are they simple. Yet, they are
worth the effort.

Gaps and knowledge and future research

Our understanding of the issues that surround RRSs is very limited. Only a few studies
have been conducted in even fewer centres. The gaps in our knowledge define the future
research agenda. We know little about the epidemiology of abnormal vital signs in
hospital patients and the outcome of patients who experience them. We know little
about the specificity and sensitivity of specific vital sign abnormalities and/or
of clusters of such signs. We do not know whether improved monitoring technology with
increased automation of vital sign recording and with advisory response systems can
decrease adverse events or improve team activation. We do not know about the anthropology
and psychology of how nurses and doctors currently respond to changes in patient status
and why they do or do not activate RRSs. We do not know what teams do at the bedside
which is useful and what they do at the bedside which is not useful. We have very
little information on how such teams affect the issuing of not-for-resuscitation orders
in ward patients who are acutely ill. We have limited knowledge of how such systems
might affect surgical patients differently from medical patients and how activation
may occur differently in different specialty areas. In short, the gaps in our knowledge
are wide and the research agenda equally big. Yet the process has just begun and there
is growing momentum in terms of clinical application and investigation. It is likely
that, once critical care physicians realise this is a new frontier for the specialty,
we will be able to start filling these gaps step by step.

Conclusion

Translating common sense into evidence for a complex intervention like MET poses enormous
challenges, and only progressive accumulation of evidence from different settings
and situations will ultimately sway physician behaviour. A conclusive randomised controlled
trial is unlikely to occur. Medical leadership needs to acknowledge the fact that
acutely ill patients in the wards should be identified rapidly and that critical care
expertise, resources, and personnel should be delivered to the bedside of the critically
ill wherever they are. In the words of the slogan of the American Society of Critical
Care Medicine, we need to deliver the 'right care, right now'. Hospital wards should
be no exception.